UK-based aerospace software startup ZEROAVIA announced today that sustainability certification body Gold Standard has approved its methodology concept to issue what could be referred to as “contrail credits.” Rather than offsetting carbon emissions directly (like carbon credits), they will offer an avenue for airlines to “make up” for the warming effects equivalent to that of carbon dioxide, by mitigating the non-CO2 climate impact of air travel. Everyone knows that aeroplanes emit copious amounts of CO2 (whether that causes any changes to our flying habits is another matter).